1. Field of the Invention
The present invention relates to an improvement of a traction type of elevator apparatus having a driving mechanism disposed in an elevator path (or hoistway) of the apparatus.
2. Description of Related Art
In recent years, especially in urban areas, it has been required to make the effective use of buildings per se. For example, for even an elevator's machine room standing on the housetop etc., the right to sunlight, the appearance of beauty, or the like have been taken into consideration.
Under such a situation, hitherto, there have been developed a variety of attempts to accommodate a control unit in the elevator path without establishing the elevator's machine room in order to provide a compact elevator apparatus. For example, Japanese Patent No. 2593288 discloses a traction sheave elevator, as shown in FIG. 1. In the figure, a flattened driving mechanism 2 having a traction sheave 1 is disposed between a side wall 3a in an elevator path 3 and a space defined by projected planes of an elevator car 4 in the upward and downward directions. A hoisting (suspension) rope 7 is wound about a sheave 5a beneath the car 4 and a sheave 5b above a balance weight 6, while both ends of the hoisting rope 7 are fixed on a top wall 3b defining the elevator path 3. Note, according to the arrangement shown in FIG. 1, a pit 3c in the elevator path 3 is positioned under a level 3d of the first floor (1F).
The elevator of FIG. 1 does adopt a structure where the car 4 is driven like a movable pulley while winding the suspension rope 7 about the sheave 5a under the car 4. Owing to this arrangement, it is possible to reduce the capacity of a motor of the driving mechanism relatively and minimize a space occupied by the driving mechanism, together with the effective use of the space above the car 4.
Japanese Unexamined Patent Publication (kokai) No. 9-156855 discloses another elevator apparatus shown in FIG. 2. In the apparatus, the flattened driving mechanism 2 is arranged in the upper space of the balance weight 6 and adapted so as to suspend the car 4 through turning sheaves 8a, 8b and 8c.
In this way, since the driving mechanism 2 having the traction sheave 1 is disposed between a side wall in an elevator path 3 and a space defined by projected planes of an elevator car 4 in the upward and downward directions, the arrangement allows to minimize a space that the whole apparatus does occupy without providing the machine room on the roof, so that the elevator apparatus can be provided while exhibiting high efficiency in utilizing the space.
In the former elevator apparatus, however, since the velocity of the moving rope is twice as much as that of the elevator car due to the adoption of "moving-pulley" driving system in accordance with the roping ratio of 2:1, various problems would be raised in case of the requirement for a high-speed elevator. In addition, as the driving mechanism is accommodated in the space between the projected planes of the elevator car and the inner wall of the elevator path, a problem still remains in terms of the requirements for the mechanism having a large capacity.
While, in the latter elevator apparatus, the velocity of the suspending rope is equal to that of the elevator car owing to the provision of the turning sheaves. Nevertheless, there is remained a problem in terms of effective use of space in the elevator path because the apparatus requires a space for accommodating the turning sheaves on the upper side of the elevator path.